Apparatus for manufacturing containers



Oct. 13, 1970 OD w. CHRISTENSSON 3,533,135

APPARATUS FOR MANUFACTURING CONTAINERS Filed 001.- 24, 1.866

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w INV EN OD W. CHRISTENSSON BY OZZQ'JQQQQQJ Jay/W ATTORNEYS UnitedStates Patent- 3,533,135 APPARATUS FOR MANUFACTURING CONTAINERS d WikarChristensson, Ekbacksvagen 32-34, Bromma, Sweden Filed Oct. 24, 1966,Ser. No. 588,834 Claims priority, application Sweden, Nov. 1, 1965,

Int. Cl.B29c 17/00 U.S. Cl. 18-19 8 Claims ABSTRACT OF THE DISCLOSURE Amethod and apparatus for forming liners onto the interior surface ofopen top stiff outer containers, wherein the liner is also attached tothe open edge of the container and thereover to the outside of thecontainer. The containers are placed in a mold with the upper side partsof the container projecting out of the mold. Support plates extendupwardly out of the mold to support the said upper side parts to preventbuckling thereof, during the drawing of the liner onto the container.

This invention relates to containers, and in particular, it relates toan apparatus for firmly attaching a flexible type lining material suchas plastic or the like to the interior surface of a container of arelatively stiff material such as cardboard or the like. Although theinvention is not limited to plastic linings and cardboard containers,for purposes of illustration and convenience the relatively flexiblelining material will be referred to as plastic material and therelatively stiff container material will be referred to as a cardboardmaterial.

It is known to place a flexible lining into an open top container byfirst placing the container into an open top die with the open end ofthe container facing upwardly, and then placing a sheet of liningmaterial over the die cavity, and subsequently attaching the lining tothe interior surface of the container by a deep drawing process usingeither pressure or a vacuum. However, serious problems have limited thesuccessful operation of this known procedure.

It is practically impossible to provide an absolutely perfect bondbetween the lining and the container. Therefore, to assure that thelining will not become loose, it is necessary to form the lining notonly on the interior surface of the container, but also on the free edgeof the container around the opening therein, and possibly also slightlybeyond the free edge onto the exterior surface of the container. Thisresult could be obtained, perhaps, by allowing the free edge of thecontainer to extend upwardly out of the die cavity. However, this wouldnot be practical since the forces exerted on the container during thedrawing process would cause that portion of the container projecting outof the die to buckle and thus yield outwardly and perhaps even tear. Ofcourse, this problem might be solved by using a very heavy material toform the container. However, this would be an avoidance rather than asolution to the problem since the heavier container material would beuneconomical, and in many instances undesirable as a packaging material.

Thus, it is a purpose of the present invention to provide an apparatusfor firmly and durably securing a flexible lining material onto acontainer of a material which is relatively stiff, for example, morestiff than the flexible lining material, but not necessarily of suchstiffness and rigidity that it could withstand buckling during thedrawing operation without the features of the present invention.

The container to be lined may be formed by punching a blank of cardboardor a similarly stiff material and ice tangular open top container fromsuch a blank it is often necessary to place certain flaps extending fromone side of the container into overlapping relationship with adjacentsides of the container. Consequently, some of the container sides willcomprise at least two layers of material while other sides will compriseonly a single layer of material. Of course it is also possible to forman open top rectangular container wherein. all the sides comprise only asingle layer of material, for example, where the sides are joinedtogether at the corners. The present invent-ion is applicable to allshapes of open top containers regardless of the number of sides formedonly by a single layer of material.

The container is then placed into an open topped die with the open topof the container facing upwardly. In practice, a large number of diesmay be formed side by side. A large sheet of flexible lining material isthen placed over all of the dies and then drawn onto the interiorsurface of the containers located in the dies by known deep drawingprocedures.

It is important that the lining material be strongly and durably bondedto the interior surface of the container material thereby forming anintimately joined unit. As noted above, it is quite difficult to obtaina strong bond between the plane sides of the interior of the containerand the lining. For this reason it is necessary to form a bond not onlyat the interior of the container but also at its upper free edge andalso for a limited extent along the outside of the container. Thisresult is obtained by allowing the upper edge of the container toproject out of the die during the deep drawing operation.

However, as noted above, it is not generally practical to allow aportion of the container to project out of the die since that portionwill then be subjected to buckling, and perhaps tearing, during the deepdrawing operation. Tests have shown that in producing generallyrectangular containers, that those sides of the container which extendabove the upper edge of the die, and are composed of only a single layerof cardboard material, will buckle, yield outwardly and even tear duringthe deep drawing opera tion. Such a container must, of course, bediscarded. Further, in some instances, a damaged container will causedamage to other containers locate-d in adjacent dies.

'One cause of container buckling is very hard to overcome. Experiencehas shown that thickness'of the lining material can vary up to -15% inone and the same sheet. When such a sheet is employed in a deep drawingoperation to form the lining, the traction power at the edges of thecontainer will be stronger or weaker depending on the thickness of thelining material at the respective edge. Thus, it is possible for astrong portion of the lining material to be located at a weak positionon the container and thereby cause buckling and tearing.

One way to overcome this buckling problem might be to place thecontainer completely within the die. However, for reasons explainedabove, it would not then be possible to obtain a strong and durable bondbetween the lining material and the interior surface of the material.

Briefly, the present invention provides an apparatus for allowing thecontainer to extend beyond the upper edge of the die while at the sametime preventing buckling of the container material.

According to the operation of the preferred apparatus of the presentinvention the container is placed into a die which is shaped tosubstantially mate with the outer surface of the container. The depth ofthe die is less than that of the container. Consequently, the upper edgeof the container will project out beyond the upper edge of the die. Toeliminate buckling of the upper edge of the container, while at the sametime allowing the lining material to be formed completely along theupper edge, a rigid support means is placed against the exterior surfaceof those container sides which are not capable of withstanding bucklingforces during the deep drawing operation. In a container of the typereferred to, the sides having only a single layer of material willrequire a support means while the sides formed by a double layer ofmaterial will not require a support means. To assure that the liningmaterial becomes attached to the upper edge of the container, thesupport means will extend upwardly along the exterior surface of thecontainer to a point short of the free edge. For example, the supportmeans may stop at 1 mm. short of the free edge. Also, the support meanswill extend for a width shorter than the width of the side beingsupported.

With the support means thus in place the sheet of lining material isplaced over the containers and applied thereto by the usual deep drawingprocedures.

According to the apparatus of the present invention, shallow recessesare formed in the sides of the die against which the sides of thecontainer requiring support will be placed. Then support plates arepositioned in these recesses in such a manner that they extend upwardlybeyond the upper edge of the die to a height slightly below the heightof the container to be placed in the die. In this manner the plates willprovide the necessary support while at the same time not interferingwith the proper placement of the lining material onto the free edge ofthe container. In one common type of rectangular container formed from apunched blank, two opposite sides of the container are formed with adouble layer of material while the other two sides are formed from onlya single layer of material and thus require support at their upper edgesduring the deep drawing operation. In a die adapted for use with such acontainer the two support plates will be located on opposite sides ofthe die. In this instance it is desireable to connect the two plates ata level below the die thereby forming the two support plates from asingle piece of material having a U-shaped cross-section, the twosupport plates forming the legs of the U. A moveable support plate maybe provided at the bottom of the die cavity both for supporting thecontainer and for thrusting the container outwardly after completion ofthe operation.

Thus, it is an object of the present invention to provide an improvedapparatus for firmly and durably fixing a flexible lining material ontoa relatively stiff container which method and apparatus overcomedisadvantages present in previous methods and apparatus.

Another object of the present invention is to provide an apparatus forproviding a strong and durable bond between a flexible lining materialand a relatively stiff container material which method and apparatus aremore economical than previously known methods and apparatus. 1

It is still another object of this invention to provide an apparatus forallowing a lining material to be placed along the free edge of an opentopped container while at the same time providing a means to eliminatebuckling of the vulnerable portions of the container.

Other objects and the attendant advantages of the present invention willbecome apparent from the detailed description to follow together withthe accompanying drawings wherein:

FIG. 1 illustrates a typical container of the type to be lined with themethod and apparatus of the present invention.

FIG. 2 shows a deep drawing die according to the present invention.

FIG. 3 is a section view of the die shown in FIG. 2 taken in the planeillustrated by the line 33 of FIG. 2.

A typical container to be lined by employing the method and apparatus ofthe present invention may be an open top rectangular container 11, asshown in FIG. 1, r example, having a bottom and upwardly divergingsides. In forming the container 11 the short sides 12 are so manipulatedthat they comprise two layers of cardboard while the long sides 13include only a single layer of cardboard. Consequently, the short sides12 offer considerably greater resistance to buckling than the long sides13.

A die 15, as shown in FIG. 2, has a generally rectangular frame, made ofa suitable material such as light metal, and having a cavity, the shapeof which is substantially mateable with the outer surface of thecontainer 11. The cavity in die 15 also includes air channel 16 runningdown the short sides of the cavity for facilitating the passage of airbetween the container 11 and the die 15 during the deep drawingoperation. During deep drawing, air in the die is of course drawn outthrough the space 20 between the side walls and the bottom plate 19. Ashallow recess 17 is provided in each of the long sides of the cavityagainst which the sides 13 of the container are to be placed. A thinside plate 18 is mounted in each recess 17, the plate being of athickness substantially equal to the depth of the recess 17. The sideplates 18 may be of any suitable material, such as for example, steel.The recesses 17 extend laterally for a distance substantially less thanthe side of the cavity in which the recess is formed; and the sideplates 18 are of a width slightly less than that of the recess 17.

During the deep drawing operation the container 11 is placed into thedie 15 to such a depth that approximately 10-20% of its overall heightextends upwardly beyond the upper edge of die 15. The Width of sideplates 18 is chosen so that they will provide sufiicient support tothose parts of the container which extend upwardly beyond the upper edgeof die 15 to prevent buckling and outward yielding of that portionduring the deep drawing operation.

As explained earlier, the purpose of having a portion of the container11 extending out of the die is to assure that the lining will be appliednot only to the interior surface of the container 11 but also to theupper free edge and slightly beyond the upper free edge onto theexterior surface of the container. Not only will this provide a morefirm and durable bond between the lining materal and the container, butit will also provide a smooth upper edge thereby facilitating theplacement of a cover onto the container. Another advantage of mountingthe container in a die in this fashion is to obtain a radially outwardlyextending flange of lining material at the top of the container ontowhich waste material can run during the filling of the container withoutstaining the usually decorative exterior surface of the container 11.

The side plates 18 may be attached to the die 15 in any suitable manner.In the preferred operation of the invention the side plates 18 aremounted Within the die 15 so that they will extend upwardly along theouter surface of the container 11 above the die 15 to a point close tobut below the upper free edge of the container 11, for example, 1 mm.below that edge. As shown in FIG. 2 and 3 the side plates are mounted atopposite sides of the cavity. Consequently, the side plates may beformed as a one-piece member having a U-shaped crosssection wherein thetwo side plates 18 form the legs of the U.

While the present embodiment illustrates fairly Wide single side plates,18, it is also possible to provide a plurality of more narrow sideplates. Of course, if the short sides 12 of the container are also weaksides formed of a single layer of material, then recesses 17 and sideplates 18 may also be provided in the short sides of the cavity.

For most etficient operation, it is preferable that the side plates 18be as thin as possible and at the same time not unnecessarily wide sincethere will be a reduction in adherence of the lining along the upperedge of the container in the area of the side plates. Of course,

this reduction in adherence should be minimized to prevent loosening ofthe liner from the container.

A vertically moveable support plate 19 is provided at the bottom of thedie both for supporting the bottom of the container 11 during the deepdrawing of the lining and also for thrusting the finished container fromthe die.

FIG. 3 illustrates the overall relationship between the elements of thedie, the container 11 and the lining 14. It can be seen that the sideplates 18 extend upwardly to a point slightly below the upper edge ofthe container 11. This allows the lining material 14 to cover at leastthe free edge of the container adjacent the side plates 18. Of course,where no side plates are present the liner material 14 may continue overthe free edge and adhere to the exterior surface of the container. Asshown in FIG. 3 the container 11 rests upon the support plate 19. Also,FIG. 3 illustrates the generally U-shaped cross-section of the sideplates as arranged in one embodiment of the invention.

The operation of the invention is as follows. In actual production agreat number of dies are usually joined together side by side and end toend. An empty container 11, which may be held together at this point bysuitable means such as glue or the like, is placed into each die 15.

A large sheet of suitable lining material is then positioned over theplurality of dies and heated to a forming temperature, and subsequentlydeep drawn into the containers in a manner known per se, such as, forexample, by vacuum and/or pressure. During this deep drawing operationthe lining material will form on the interior of the container and alsoalong the free edge. The force exerted on the package will not bucklethe package or cause it to yield outwardly since those sides of thecontainer requiring additional support are mounted adjacent a side plate18. The package thus formed is then pushed out of the die by thevertically moveable support plate 19 and moved into another compartmentfor filling and sealing.

Thus, with the present invention it is possible to avoid buckling andyielding of the upper edge of the container above the die 15 during theforming of the lining, while at the same time it is possible to producethe container of a cheaper cardboard material. Further, since the riskof buckling and outward yielding has been eliminated, it is possible toincrease the speed with which the lining can be applied to thecontainer. Thus, the present invention obtains a higher production rateand a more durable bond between the lining and the container whileemploying a less expensive container material.

While the invention has been described in considerable detail above withrespect to a preferred method of operation and respect to a preferredembodiment of the apparatus, it should be apparent that the invention iscapable of numerous variations and modifications within the spirit andscope of the invention as defined in the appended claims wherein:

I claim:

1. A die apparatus for use in forming a lining in a containercomprising: a cavity formed in said die having an open top bounded by afree edge and an interior surface formed by a bottom and a plurality ofside walls between said bottom and said free edge, an opening throughsaid cavity interior surface for gas communication with the interior ofthe cavity other than through the open top said cavity beingsubstantially mateable with the outer surface of a container to belined, at least one side wall having a recess formed therein, saidrecess extending horizontally along said side wall for a distance lessthan the width of said side wall, and a side plate mounted in saidrecess and extending upwardly out of said die beyond said free edge,said plate being thin and generally parallel to the side wall in whichit is mounted.

2. An apparatus as claimed in claim 1 wherein the bottom of the cavityis formed by a vertically moveable support plate for supporting the saidcontainer.

3. An apparatus as claimed in claim 1 wherein said cavity has an evennumber of sides and wherein there is provided at least two side plates,each one being mounted in a recess in opposite side walls of saidcavity.

4. An apparatus as claimed in claim 3 in which said two side plates arejoined together at their lower ends to form a member having a U-shapedcross-section.

5. An apparatus as claimed in claim 4 in which horizontal lines lying inthe planes of each of the said two side plates are substantiallyparallel to each other.

6. An apparatus as claimed in claim 1 wherein the depth of the saidrecesses is substantially equal to the thickness of the said side plate.

7. An apparatus as claimed in claim 1 wherein at least one of the cavitywalls without a recess formed therein for a side plate has formedtherein a vertically extending channel to facilitate flow of fluidtherethrough.

8. An apparatus as claimed in claim 1 in which the side plate is madefrom a thin steel material.

References Cited UNITED STATES PATENTS 231,508 8/1880 Thompson 249-112XR 696,686 4/1902 Lyons 249-112 XR 776,979 12/1904 Williams 18-38974,350 11/1910 Bratton 2491l2 XR 1,019,506 3/1912 McCool 18-381,206,150 11/1916 Slick. 1,257,230 2/1918 Higgenbotham 249112 XR1,787,503 1/1931 Zube 1844 XR 1,896,372 2/1933 Rieser 18-19 XR 1,919,0707/1933 McKay et al. 18-19 1,951,071 3/1934 Stripe 249-112 2,479,350 8/1949 Haggart 18-42 3,121,258 2/1964 Lagler.

WILLIAM J. STEPHENSON, Primary Examiner U.S. Cl. X.R. l8-35, 44

